[rescue] Re: Old sparcstations & overheating

Skeezics Boondoggle skeezics at q7.com
Sat Feb 19 04:28:13 CST 2005

On Sat, 19 Feb 2005, "Janet L. Campbell" wrote:

> Since the drives and the mainboard are located in different air paths in
> the SS20, hot drives are unlikely to kill the processors.  However, with
> hot drives, the failure rate of the upper drive seems to be noticably
> higher.  Make sure you have the hard drive fan FCO installed (looks like a
> mini fan between the CDROM/floppy and hard drive bays). You're running

Does that little fan for the drives _really_ do that much? :-)  I've run 
lots of SS20s but always with just one disk - for root+swap, basically - 
and mounted the rest off the network or an external enclosure.  The 20's 
only real weakness is its cooling... otherwise it's a great box, that 
packs a lot of power in a very small space.

> SM81s, which weren't technically qualified in the SS20, but I've done it
> too and they work fine in reasonable weather.

Yes, in a properly cooled environment, SM81s (the 1MB version) are awesome 
in the '20.  Faster, in some cases, than the early Ultra 1s (for heavy I/O 
tasks, for example).

> Removing the side panels is easy and gives you a little extra airflow, 
> late-model SS20s (and SS4/SS5s) had side panels with a more open flow 
> design.  I seem to remember them being mandated with certain high-heat 
> cards, like the TZX.

Well, running a pizzabox machine without skins offends my aesthetic 
sensibilities. :-)

However, I discovered that the CPU fan from an Ultra 1 fits perfectly
between the motherboard and the metal frame.  Secured with tie wraps, and
a quick solder or crimp job to attach a power connector (routed into the
drive area) I've fitted a pair of those to supplement the cooling in my
machines at home (quad-HS125, quad-SM51, dual-SM71 & dual-SM81).  Drives
are cheap and easy to replace, but Mbus modules, memory and Sbus cards
will eventually become scarce... so I'm far more concerned about airflow
at the back of the chassis where those components live than the drive

> The biggest heat problems don't come from the largest capacity drives, but
> rather from those with the most cutting technology at the time.  The
> early-generation Barracudas (pioneering 7200RPM drive technology) put out
> a lot of heat and would burn up without proper airflow.

Not to mention that those early 2.1GB 'cudas are *frightfully* LOUD.  As
in, measured with a meter, louder than a SC2000 with four blowers loud.  
Give ya tinnitis loud.  They're really damned loud! :-)

But even without extra cooling, you have to admire how tough the old Sun
boxes are.  I had the task of rebuilding an SS20 at work once that was
hiding under a pile of papers at the back of a carpeted cubicle - with two
CPUs, a full load of memory, floppy + CDROM, and *two* early 2GB Seagates.  
(I think they'd surrounded the box to help cover up the noise!)  I was
stupified that the box ran as long as it did with all of its vents blocked
or *choked* with dust - it looked like a lint screen after washing a load
of sweaters - without bursting into flames.  Despite that kind of abuse,
and the fact that the top drive did in fact die of heat death, once we
replaced both drives with a newer, quieter, faster 9GB it ran for another
two years before it was finally retired.  I love SS20s. :-)

-- Chris

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